There are currently two primary wayside detection systems for monitoring the health of freight railcar bearings in the railroad industry: The Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). TADS™ uses wayside microphones to detect and alert the train operator of high-risk defects. However, many defective bearings may never be detected by TADS™ since a high-risk defect is a spall which spans about 90% of a bearing’s raceway, and there are less than 30 systems in operation throughout the United States and Canada. HBDs sit on the side of the rail-tracks and use non-contact infrared sensors to acquire temperatures of bearings as they roll over the detector. These wayside bearing detection systems are reactive in nature and often require emergency stops in order to replace the wheelset containing the identified defective bearing. Train stoppages are inefficient and can be very costly. Unnecessary train stoppages can be avoided if a proper maintenance schedule can be developed at the onset of a defect initiating within the bearing. Using a proactive approach, railcars with defective bearings could be allowed to remain in service operation safely until reaching scheduled maintenance. The University Transportation Center for Railway Safety (UTCRS) research group at the University of Texas Rio Grande Valley (UTRGV) has been working on developing a proactive bearing condition monitoring system which can reliably detect the onset of bearing failure. Unlike wayside detection systems, the onboard condition monitoring system can continuously assess the railcar bearing health and can provide accurate temperature and vibration profiles to alert of defect initiation. This system has been validated through rigorous laboratory testing at UTRGV and field testing at the Transportation Technology Center, Inc. (TTCI) in Pueblo, CO. The work presented here builds on previously published work that demonstrates the use of the onboard condition monitoring system to identify defective bearings as well as the correlations developed for spall growth rates of defective bearing outer rings (cups). The system first uses the root-mean-square (RMS) value of the bearing’s acceleration to assess its health. Then, an analysis of the frequency domain of the acquired vibration signature determines if the bearing has a defective inner ring (cone) and the RMS value is used to estimate the defect size. This estimated size is then used to predict the residual life of the bearing. The methodology proposed in this paper can assist railroads and railcar owners in the development of a proactive and cost-efficient maintenance cycle for their rolling stock.

The railroad industry currently utilizes two wayside detection systems to monitor the health of freight railcar bearings in service: The Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). TADS™ uses wayside microphones to detect and alert the conductor of high-risk defects. Many defective bearings may never be detected by TADS™ since a high-risk defect is a spall which spans more than 90% of a bearing’s raceway, and there are less than 20 systems in operation throughout the United States and Canada. Much like the TADS™, the HBD is a device that sits on the side of the rail-tracks and uses a non-contact infrared sensor to determine the temperature of the train bearings as they roll over the detector. These wayside detectors are reactive in the detection of a defective bearing and require emergency stops in order to replace the wheelset containing the defective bearing. These costly and inefficient train stoppages can be prevented if a proper maintenance schedule can be developed at the onset of a defect initiating within the bearing. This proactive approach would allow for railcars with defective bearings to remain in service operation safely until reaching scheduled maintenance. Driven by the need for a proactive bearing condition monitoring system in the rail industry, the University Transportation Center for Railway Safety (UTCRS) research group at the University of Texas Rio Grande Valley (UTRGV) has been developing an advanced onboard condition monitoring system that can accurately and reliably detect the onset of bearing failure using temperature and vibration signatures of a bearing. This system has been validated through rigorous laboratory testing at UTRGV and field testing at the Transportation Technology Center, Inc. (TTCI) in Pueblo, CO. The work presented here builds on previously published work that demonstrates the use of the advanced onboard condition monitoring system to identify defective bearings as well as the correlations developed for spall growth rates of defective bearing outer rings (cups). Hence, the system uses the root-mean-square (RMS) value of the bearing’s acceleration to assess its health. Once the bearing is determined to have a defective outer ring, the RMS value is then used to estimate the defect size. This estimated size is then used to predict the remaining service life of the bearing. The methodology proposed in this paper can prove to be a useful tool in the development of a proactive and cost-efficient maintenance cycle for railcar owners.

This paper provides an overview of the design of natural ventilation systems to control smoke movement in rail tunnels. The paper discusses the current industry standards and design requirements for tunnel emergency ventilation systems, and then addresses the various technical elements that are used to design such systems. These technical elements include parameters in the direct control of the designer, as well as those that are beyond the control of the designer. The paper also presents a case study where various physical design elements are utilized to create a working natural ventilation smoke control system for a short rail tunnel.

The new train signaling, traction power and tunnel ventilation system coordination guidelines enacted in National Fire Protection Association (NFPA) Standard 130 have brought the necessity and cost of tunnel ventilation fan shafts into greater focus. The guidelines were aimed at coordinating the three aforementioned rail systems to control the number of trains that could be between successive ventilation shafts during an emergency — in recognition of the fact that the best protection to both incident and non-incident train passengers and crew is to allow no more than one train in each ventilation zone. Though based in safety, these new NFPA guidelines can substantially expand the capital cost and environmental impact of new rail tunnel projects by adding more ventilation shafts and tunnel fan equipment to the scope of work. In addition, the resulting increase in the required number of ventilation shafts and tunnel fan equipment can hinder existing railroad properties as they seek to either increase their train throughput rates, or reduce their tunnel electrical infrastructure. Fortunately, a new kind of emergency ventilation shaft has been developed to facilitate compliance with the NFPA 130 Standard without the excessive capital cost and far-reaching environmental impacts of a traditional emergency ventilation shaft. This new kind of emergency ventilation shaft is called the Crossflue. The Crossflue is a horizontal passage between parallel rail tunnels with a single ventilation fan-motor unit installation. The Crossflue fan is designed to transfer air/smoke flows from one (occupied, incident) tunnel to another (unoccupied, non-incident) tunnel — thereby protecting the incident tunnel at the expense of the non-incident tunnel. The Crossflue passage has angled construction to allow a smooth transition of airflows both into and out of the adjoining tunnels. In addition to the fan, the Crossflue contains a ventilation damper, sound attenuators, ductwork transitions and flexible connectors within the fan equipment line-up; the functionality of all this mechanical equipment is described in the paper. To preserve underground space and minimize the rock excavation, the Crossflue fan is both remotely-powered and remotely-controlled; the fan is only operated as part of a pre-programmed response to tunnel fire events. The methodology utilized to design the Crossflue was taken from the Subway Environmental Design Handbook (SEDH); the SEDH [1] was specifically developed for rail tunnel ventilation design and is the preeminent reference volume in the industry. In summary, the Crossflue provides a dual benefit of achieving NFPA 130 compliance, while at the same time minimizing the construction, equipment, environmental, and energy costs of a traditional tunnel ventilation shaft.

Crude oil and ethanol unit train derailments sometimes result in the release of large volumes of flammable liquids which ignite and endanger the safety of persons, property, and the environment. Current methods to reduce the probability and mitigate the consequences of High-Hazard Flammable Train (HHFT) derailments include operational speed constraints, enhanced tank car design/build requirements, improved car and track inspection and maintenance, and use of advanced braking systems. The train brake system can dissipate more energy in a derailment scenario if the brake signal propagation rate is increased, the brake force against the wheel tread is increased, or a combined approach is used. This paper describes a simplified energy conservation model used to determine the emergency braking stopping distance and energy dissipation benefits available for three advanced train braking systems. A 3×3 matrix of brake configurations was defined by three brake signal propagation rates and three car net braking ratio (NBR) values. The brake signal propagation rate was modeled for trains with conventional head-end locomotive power, pneumatic car braking, and no two-way end-of-train device (CONV); locomotive distributed power with pneumatic car braking (trailing DP); and locomotive power with electronically-controlled pneumatic (ECP) braking. Car NBR values of 10, 12.8, and 14 percent were selected to reflect the expected brake force range available from older equipment in the existing tank car fleet (10% NBR) to the maximum acceptable value for new or rebuilt cars (14% NBR). Various in-train emergency brake application scenarios for loaded unit trains were modeled while accounting for the gross effects of derailment/collision blockage forces. Empirical data from four trailing distributed power train derailment events were used to estimate an average derailment/collision blockage force (ADF) and simulate the trailing consist braking performance. The ADF results were subsequently used in a more general tank car unit train parametric study to evaluate the effects of train speed, track grade, and in-train derailment position for each brake configuration in the matrix. The simplified energy conservation model was used to 1) quantify the number of trailing consist cars expected to stop short of the derailment location and 2) compare the car-by-car energy state of each car in the trailing consist that was calculated to reach the derailment location. Results for the empirical and parametric study cases are compared graphically and observations are discussed relative to two assumed baseline brake configurations.

From the original “steam trumpet” built for locomotives in 1832 by the Leicester and Swannington Railway to modern air-pressure horns, train warning signals have not changed significantly in nearly 200 years. The effectiveness of train warning signals has been of particular concern for trespassers listening to music with headphones. The authors have conducted research as part of a Federal Railroad Administration program to design and assess the effectiveness of candidate new emergency warning signal (EWS) sounds. This paper summarizes a literature review to understand the needs for a new EWS sound and principles of audible signal detection. Acoustic measurements were conducted of headphones to understand in-ear music levels and active and passive sound attenuation. Candidate EWS sounds were developed with a goal of maintaining the identification of a train approaching and increasing the sense of urgency and response time for trespassers to vacate the tracks. Testing of candidate EWS sounds was conducted in an audio booth and on-board a moving locomotive. The research results have shown that a new EWS sound can maintain the association of a train approaching, increase the sense of urgency, reduce the reaction time for trespassers to vacate the tracks and improve safety on railroad corridors.

Twenty-three commuter and inter-city passenger train accidents, which occurred over the past twenty years, have been analyzed. The analysis has assessed the potential effectiveness of various injury mitigation strategies. The strategies with the greatest potential to increase passenger safety are interior occupant protection, coupler integrity, end structure integrity, side structure integrity, and glazing system integrity. We recommend that these strategies be researched further. Three types of accidents were analyzed: train-to-train collisions, derailments, and grade-crossing collisions. Train-to-train collisions include the commuter train-freight train collision in Chatsworth, California on September 12, 2008. In Chatsworth a commuter train collided with a freight train at a closing speed of ∼80 mph, fatally injuring twenty-five people and injuring more than 100 others. Derailments include the commuter train derailment in Spuyten Duyvil, New York on December 1, 2013, fatally injuring four people and injuring more than fifty others. Grade-crossing accidents include the commuter-SUV collision in Valhalla, New York on February 3, 2015, which resulted in six fatally injured people, including the SUV driver, and thirteen severely injured people. Four categories of mitigation strategies were considered: train crashworthiness, wayside structure crashworthiness, fire safety, and emergency preparedness. Within each of these categories are equipment features, which may potentially be modified to further mitigate injuries. The features are simple noun phrases, e.g., “floor strength,” implying that the floor strength should be increased. Train crashworthiness includes features such as end strength, floor strength, coupler separation, and numerous others. Wayside structure crashworthiness includes features such as frangible catenary poles and third rail end caps. Fire safety includes train interior and train exterior features for minimizing the potential for fire and for reducing the rate at which fire might spread. Emergency preparedness includes features for emergency egress, access, lighting, signage, and on-board equipment, such as fire extinguishers. Overall, rail passenger travel has a high level of safety, and passenger train accidents are rare events. The numbers are low for expected casualties per passenger-mile and casualties per passenger-trip. A high level of safety, however, does not mean efforts to improve it should cease. But it does mean that crashes are rare events. Rare events in complex systems are notoriously difficult to analyze with confidence. There are too few accidents to provide the data needed for even a moderate degree of mathematical confidence in statistical analysis. Analyses of similar data in medical and scientific fields have been shown to be prone to the biases of the researchers, sometimes in subtle and difficult-to-detect ways. As a means of coping with the sparse data and potential biases, the goal has been to evaluate the accidents transparently and comprehensively. This approach allows a wide audience to understand how injuries and fatalities occur in passenger train accidents and, most importantly, allows us to prioritize mitigation strategies for research.

GSM-Railways (GSM-R) is the current standard for railway voice and data communication. GSM-R provides railway specific voice services, such as Railway Emergency Call (REC). GSM-R provides also the European Train Control System (ETCS), which offers in-cab signaling and Automatic Train Protection (ATP). Despite these features and services, GSM-R has various major shortcomings. Therefore, alternative technologies are considered to replace GSM-R and become the next generation railway mobile communication network. 3GPP Long Term Evolution (LTE) is a likely candidate for GSM-R replacement. LTE is more efficient, flexible and offers much higher capacity, which allows the railway network to provide new communication-based applications for railways. Most of the research on LTE in railways has been focused on data-based railway applications (ETCS signaling and other). Nevertheless, voice communication is still a crucial service for railways. Regardless of its advantages, LTE can only become a railway communication technology if it provides voice communication fulfilling railway requirements. This paper presents how Voice over LTE (VoLTE) can be used to build railway communication services. Examples of Railway Emergency Call and One-to-One Call are provided. Service performance, in terms of call setup times and voice transmission quality, is analyzed in simulation scenarios modelling two railway scenarios in Denmark.

Union Pacific Railroad’s Moffat Tunnel Subdivision, west of Denver, Colorado, was significantly impacted by an approximately 500 to 1,000 year storm event that occurred between September 9, 2013 and September 13, 2013. As a result of this historic event, washouts, earth slides, and debris flows severely impacted track infrastructure by eroding track embankments, destabilizing surrounding native slopes, and overwhelming stormwater infrastructure. Emergency response activities performed to restore track operations at Milepost (MP) 25.65 and MP 22.86 required the integration of civil, hydraulic, environmental and geotechnical engineering disciplines into emergency response and construction management efforts. Additionally, support from UPRR’s Real Estate Division was required when addressing private ownership and site access issues. The following text summarizes how coordinated efforts between various groups worked together in a pressure setting to restore rail service. The most significant damage occurred at MP 25.65 in a mountainous slot canyon between two tunnels accessible only by rail and consisted of a washout, approximately 200 feet (61 m) in length with a depth of 100 feet (30 m). MP 22.86 experienced slides on both sides of the track resulting in an unstable and near vertical track embankment which required significant fill and rock armoring. In addition to the embankment failures at MP 22.86, flood flows scoured around the underlying creek culvert, further threatening the geotechnical stability of the track embankment. The storm event highlighted the vulnerability of fill sections, where original construction used trestles. The repair plan engineered for MP 25.65 was developed to restore the lost embankment fill to near pre-flood conditions while limiting environmental impacts in order to minimize regulatory permitting requirements. Fill replacement performed during the initial emergency response was completed within 22 days, notwithstanding site remoteness and difficult access. Repair of the embankment required the placement of approximately 90,000 cubic yards (68,800 cubic meters) of fill and installation of four 48-inch (122-cm) culverts. Repair of embankment sloughing and scour damage at MP 22.86 was accomplished without the need for environmental permits by working from above the ordinary high water mark, using a “one track in – one track out” approach while restoring infrastructure to pre-flood conditions. A new headwall to address flow around the culvert inlet received expedited permit authorization from the U.S. Army Corps of Engineers by limiting the construction footprint through implementation of best management practices and minimizing placement of fill below the ordinary high water mark. Service interruptions, such as those at MP 22.86 and MP 25.65, require sound engineering practices that can be quickly and efficiently implemented during emergency response situations that often occur in less than ideal working environments. Track outages not only impact the efficiency of a railroad’s operating network, but also impact interstate and global commerce as transportation of goods are hindered. The need to have a team of experienced engineering and construction professionals responding to natural disasters was demonstrated by this storm event.

Software algorithms are used in Positive Train Control (PTC) systems to predict train stopping distance and to enforce a penalty brake application. These algorithms have been shown to be overly conservative, leading to operational inefficiencies by interfering with normal train operations. A braking enforcement algorithm that can safely stop trains to prevent authority and speed limit violations without impacting existing railroad operations is critical to successful widespread implementation of PTC. Due to operational issues observed with early PTC braking enforcement algorithms, a number of techniques are proposed and evaluated to improve the operational efficiency of these algorithms, with emphasis on applicability to PTC systems currently being implemented. Transportation Technology Center, Inc. (TTCI) is employing a new methodology for evaluation of braking algorithms that uses Monte Carlo simulation techniques to statistically evaluate the performance of the algorithm, with limited need for field testing to verify the simulation results. In the Monte Carlo process, computer simulations are run repeatedly using randomly selected input values to predict the resulting probability distribution of stopping locations. The method provides a higher level of confidence in algorithm performance with reduced time and cost compared to traditional methods, which rely heavily on field testing. For freight trains, the method utilizes a detailed train dynamics simulation model previously developed and validated by the Association of American Railroads (AAR). For passenger trains, TTCI is developing and validating a new model capable of simulating brake systems and components specific to passenger and commuter equipment. New methods for addressing operational efficiency of braking algorithms focus on improving the accuracy of stopping distance prediction and reducing the potential variation from the prediction. Techniques investigated by TTCI include adaptive functions, which measure train braking performance en route and adapt the algorithm to these characteristics; emergency brake backup, which uses feedback following a penalty application to determine if additional emergency braking is required to stop the train short of the target; an improved target offset function, which relies on statistical multi-variable regression of thousands of stopping distance simulations; and including information about dynamic braking effort in the stopping distance prediction. Results from TTCI’s investigations show potential to reduce the operational impact, by demonstrating the probability of stopping excessively short of the target is significantly less than that of previous algorithms. The techniques are already being adopted by PTC onboard suppliers for the largest North American railroads, and many are applicable to railways worldwide.

This paper describes a numerical procedure to examine the holding forces needed to secure a cut of railroad tank cars staged on a grade during loading and unloading operations. Holding forces are created by applying emergency brake systems and blocking (or chocking) wheels. Moreover, the holding force to secure the cut of cars must be greater than or equal to the gravitational component of force acting on the cars that is parallel to the grade. Engineering statics are applied to examine the forces acting on the individual cars resting on an inclined plane. An equation to calculate holding force is developed that includes two types of factors: constants (i.e. nonrandom or deterministic factors) and probabilistic variables (i.e. factors with inherent uncertainty or randomness). The numerical procedure applies Monte Carlo simulation techniques to study the uncertainties in the engineering analysis. The Monte Carlo approach is well suited to study the uncertainties and inherent variability associated with some of these factors. The factors assumed to be deterministic in this procedure are: steepness of the grade, total number of cars on the grade, number of cars with hand brakes applied, number of chocked wheels, and weight of the tank cars. The factors treated as random variables are: tension in the hand brake chain, mechanical efficiency in the linkages of the brake system, coefficient of friction between the brake pad and the wheel, and the coefficient of friction between the chocks and the rail. Probability distributions are assumed for each of the random variables. In addition, a probabilistic sensitivity analysis is conducted to examine the relative effect of the random variables on the reliability of the braking system to secure the cut of tank cars on a grade.

In the last 7 significant accidents on the railways in GB there have been 60 passenger fatalities. 14 of these have been caused by ejection (passengers being thrown from the train during the course of the collision). One additional fatality was attributed to an object entering the carriage through the train window. In total there have been 26 ejections with over 50% resulting in fatality. The trend has been towards higher speed incidents involving vehicles overturning. The authority responsible for setting Safety Standards and, conducting research on behalf of the Train Operators and Stakeholders in GB’s railways is the Rail Safety and Standards Board (RSSB). They initiated a multi faceted stream of research to investigate the performance of glazed systems in train incidents. The aim of the research was to identify and establish measures which replicate the conditions to which glazed systems may be subject to in collision conditions and to formulate corresponding performance requirements designed to prevent passenger ejection. The research was phased and entailed the following: • Accident investigation and analysis, detailed vehicle examination. • Review of 600 passenger witness statements, obtained by British Transport Police. • Generation of computer models using the MADYMO code and Side Impact Dummy (SID) to model the overturning event in a variety of conditions. • Postulation of events and measures based on analysis. • Proposed test programme. • Construction of new test apparatus. • Construction of existing glazed units — benchmarking process. • Construction of glazed units of improved design utilising different glass specifications and laminations but capable of being fitted into existing frames. • Testing, reporting, stakeholder reviews and the production of a new equipment standard for glass in railway vehicles. The research team was keen to include a glazing company capable of providing the highest level of technical support. Independent Glass, a Scottish company had been making significant strides in improving the penetration performance of glazed units (especially at the extremes of ambient temperature conditions) was chosen to produce glass samples for the project. A significant amount of testing was undertaken at their premises in Glasgow. Additionally the new tests were undertaken which demonstrate improved penetration resistance by heavy objects and improved passenger containment. This research has been embedded in the proposed new RSSB standard “GM/RT 2100” [1] which has developed a new scenario based sequential testing regime for glazed laminated systems in railway vehicles. This paper will inform the audience of these new requirements and the research which led to its introduction. It will show the testing that has been undertaken from the perspective of the glazing manufacturer and will detail the equipment that is required to be able to perform these new tests. It will comment on the cost and mass implications of fitting these new glazing units to vehicles in GB and the safety benefit of doing so. Toughened windows are still being used by some train operators for emergency egress; however most operators are now converting their vehicles to having entirely laminated units in vehicles. This is not the subject of this paper.

The purpose of this IEEE and Transit IDEA project was to develop and test a device to give rail transit personnel and train operators advance warning of dangers well in advance of entering the danger zones such as approaching train and other potential dangers such as Fire, Chemical, and Biological Releases. This device can provide a reliable way of giving the track worker; train operator and emergency responders a warning in enough time to avoid potential accidents, injuries, or death. Further this device cuts down on incident response time from the Operational Control Center to Command Center to provide additional security and eliminate lost response time. The information provided in this report will enable other rail rapid transit agencies the ability to consider using such devices to give early warning of approaching trains and other dangers to track workers, track walkers, track inspectors, emergency responders and signal personnel and also to give the train operator early warning of the presence of personnel in the track area as well as other dangers ahead.

Following National Transportation Safety Board (NTSB) recommendations and directions from early 1996, the Washington Metropolitan Transit Authority (WMATA) has worked to provide the latest crashworthiness and passenger safety requirements for its new car procurements. Taking advantage of recent developments in the field of vehicle crashworthiness, new technical requirements were developed and implemented for the 5000 and 6000 series vehicles. To date, WMATA is the first transit authority in the U.S. to require a dynamic sled test per the APTA SS-C&S-016-SS Standard, and the second (after the New York City Transit Authority) to run full-scale vehicle crash tests. Previously, the strength-based philosophy was used to ensure some level of rail vehicle crashworthiness. However, WMATA is now implementing a strength-based crashworthiness approach, augmented with “energy-based” requirements. Should a collision occur, the Authority’s ultimate goal is to reduce passenger deceleration rates during a collision, while at the same time controlling the absorption of collision energy in a manner that minimizes loss of space in the occupied volume of the vehicle. The passenger survivability measure using maximum acceleration has been supplemented by introducing the duration of the acceleration as an additional criteria following the Head Injury Criteria (HIC) and Abbreviated Injury Scale (AIS) approaches developed for the automotive industry. WMATA’s crashworthiness requirements now include sustaining a hard coupling without any damage to the body or coupler (except emergency release), and head-on collision of two eight-car trains with specified passenger loads (one train stationary with brakes applied) with no permanent deformation of the passenger compartment and with the acceleration, level and duration not to exceed the specified HIC. The implementation of an “energy-based” crashworthiness approach was divided into several logical steps/stages. During the design process, several modifications were introduced to optimize crashworthiness and to ensure structural compatibility with the existing fleet. The design was verified by implementing full-scale testing, and potential passenger injuries were assessed by using instrumented anthropomorphic test devices (ATDs), and measuring the forces and accelerations acting on these ATDs during the test.

Most railway trains use an End of Train (EOT) device to communicate from the front of the train to the end of the train. The wireless protocol for these communications is not secure. This would allow a hostile person to initiate at will an emergency braking event with most freight and passenger trains. This paper examines the vulnerability and recommends a new protocol to reduce the threat. The protocol is backwards-compatible with the current protocol.